- Have had Type 1 diabetes mellitus for more than 5 years, and are exhibiting 1 of the following, despite intensive insulin management efforts: a) hypoglycemic unawareness, as defined by inability to sense hypoglycemia until the blood glucose falls to less than 54 mg/dL; b) metabolic instability, with 2 or more episodes of severe hypoglycemia (defined as an event with symptoms consistent with hypoglycemia in which the patient requires the assistance of another person and which is associated with a blood glucose below 54 mg/dL) or 2 or more hospital visits for diabetic ketoacidosis over the last year; or c) despite efforts at optimal glucose control, progressive secondary complications of diabetes as defined by retinopathy, nephropathy, or neuropathy.